JPH01284863A - Toner - Google Patents

Abstract

PURPOSE:To improve the rising of the electrification and the stability of the toner, even in the case of rapidly copying by incorporating a prescribed amount of a thermoplastic resin having a specified mol.wt. and a wax having a specified viscosity respectively, in the toner. CONSTITUTION:The toner is composed of at least one of the thermoplastic resin (A), the wax (B) and a coloring agent (such as a carbon black) respectively. And, the component (A) is composed of the resin (such as a styrene-acrylic type resin) capable of satisfying the inter-relationship shown by the formula 1,000<=Mn<=7,000, 40<=(Mw/Mn)<=70, 200<=(Mz/Mn)<=500 (wherein Mn is a number-average mol.wt., Mw is a weight-average mol.wt., and Mz is a Z-average mol.wt.). And, the component B is composed of the wax (such as a low mol.wt. polypropylene) having 100-180cps viscosity at the 160 deg.C and is incorporated in the toner in an amount of 2-10pts.wt. per 100pts.wt., of the component (A).

Description

[Detailed description of the invention] Industrial applications The present invention relates to an electrophotographic toner.

Prior Art and Issues In recent years, electrophotographic copying machines have become faster and faster. Some such high-speed copying machines can print 65 or more A-4 size sheets per minute, and the copying speed is 40 cm/sec or more. Note that in this specification, the copying speed refers to the peripheral speed of the photoreceptor.

Examples of toners suitable for medium-low copying speeds of 30 cm/sec or less include Japanese Patent Publication No. 55-6895,
There are oil-less donors disclosed in Japanese Patent Publication No. 58-58664, Japanese Patent Publication No. 52-3304, etc.

The oil-less donor is constructed by combining a resin with a molecular weight dispersion ratio of 3.5 to 40 and a low molecular weight wax such as polypropylene.

When the oilless donor is used in a copying machine having a copying speed of 30 cm/sec or less, the fixing strength and non-offset width are sufficiently wide, and it can be used without any practical problems.

However, if the speed exceeds 30 cm/see, especially 40 cm/s
In high-speed copying machines that exceed ea, the developing device is also driven at high speed, and the agitation of the developing device and rotation of the developing sleeve become high speeds, so conventional low- to medium-speed toner developers are used as is. It is not possible.

For example, during intermittent copying, the toner charge amount gradually increases, resulting in a problem that the image density (ID) decreases.

In terms of fixability, if the viscosity of the resin is simply lowered in order to increase the fixing strength, the heat-resistant storage stability will deteriorate and high-temperature offset will likely occur. Furthermore, since the toner is not easily released from the fixing roller, when double-sided copying is performed, the separation claw leaves marks on the copy.

In addition, since the rotation speed of the developing sleeve is fast, toner scatters from the carrier due to centrifugal force, which contaminates the area around the developing device.Furthermore, the contaminated toner appears as toner droplets on the copy, or scatters. The resulting toner forms a capri on the photoreceptor and is developed, resulting in a decrease in image quality.

Furthermore, if a toner with normal fixing strength is used for fixing, power consumption of 1.5 KW or more is required, so the power source of a high-speed copying machine is 200V.

It requires it. However, in a general office, 200vo
lt is a special construction project, so a high-speed copying machine with a capacity of 65 sheets or more that can be used at 100 volts is desired.

Problems to be Solved The present invention solves the above-mentioned problems, provides a toner suitable for high-speed copying, has excellent charge build-up and stability even during such high-speed copying, and is suitable for transfer paper, etc. The purpose of the present invention is to provide a toner that has good fixing properties and separability from a fixing roller, and can provide good images.

Means for Solving the Problems, That is, the present invention provides a toner comprising at least a thermoplastic resin, a wax, and a colorant, and the thermoplastic resin has a number average molecular weight (Mn) and a weight average molecular weight (!h).
), and Z average molecular weight (Mz) is 1.000≦Mn
≦7,000 40≦Mw/Mn≦70 200≦Mz/Mn≦500, and the viscosity of the wax at 160°C is 1
00 to 180 pps, and the wax is comprised of 2 to 10 parts by weight based on 100 parts by weight of the thermoplastic resin.

The toner of the present invention comprises at least a thermoplastic resin, a wax, and a colorant.

The thermoplastic resin used in the present invention is not particularly limited, but
Any material may be used as long as it has a sufficient softening point at the fixing temperature and a glass transition point sufficient for storage stability.

The softening point of the thermoplastic resin suitable for the present invention is determined by the development speed and the mechanism of the system, as long as the effects of the present invention are not impaired.
At least one diol component selected from the group consisting of a thermoplastic resin having a low softening point, such as polystyrene, a copolymer resin of styrene and acrylic ester or methacrylic ester, bisphenol diol, rosin diol, and glycol; Synthesized from trimellitic acid and at least one dicarboxylic acid selected from the group consisting of aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid, and aliphatic dicarboxylic acids such as phthalic acid, maleic acid, and adipic acid. Examples include polyester cross wheels. The fixing temperature may be appropriately set in consideration of the softening point of the selected thermoplastic resin. At that time, as the molecular weight of the resin used,
The relationship between number average molecular weight (Mn), weight average molecular weight (Mw), and Z average molecular weight (Mz) is 1.000≦Mn≦7,
000 40≦M w / M n≦70 200≦Mz/Mn≦500, and the number average molecular weight (Mn) is further 2゜0
It is preferable that 00≦Mn≦7.000.

The wax used in this invention is a low molecular weight polypropylene. The amount used is 2 to 10 parts by weight, preferably 2 to 6 parts by weight, per 100 parts by weight of the thermoplastic resin.

The purpose of the present invention is to improve the fixing properties of toner to transfer paper, etc. during high-speed development, and the separability of toner from a fixing roller. This is achieved by using the above-mentioned constant ratio to the plastic resin, and if even one of these conditions is lacking, a satisfactory toner cannot be obtained. In particular, the toner of the present invention has a system speed of 3
It is also suitable for development systems that exceed 0 cm/sec and even 40 cm/sec.

The toner of the present invention can also be applied to copying machines with low and medium speed development.
When the toner of the present invention is used in place of a commonly used toner, the heater capacity of the fixing device may be reduced.

In addition, the average molecular weight (Mn, M
GPC (gel permeation chromatography) is used to measure GPC (gel permeation chromatography), which separates polymers and low molecules based on the speed at which a polymer dissolved in a solvent passes through a gel such as polystyrene. This is detected using a differential refractometer or the like and converted to standard polystyrene.

Further, the viscosity of the wax is a value measured using a B-type viscometer.

Specific examples of colorants that can be used in the present invention include black pigments such as carbon black such as channel black and furnace black, acetylene black, lamp black, and aniline black; yellow pigments such as yellow lead, zinc content, Cadmium Niro, Yellow Iron Oxide, Mineral Fast Yellow, Nickel Titanium Yellow, Naphthol Yellow, Naphthol Yellow S1 Hansar Yellow G, Hansar Yellow 10G, Benzidine Yellow 61 Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow, NCG, Tartrazine Lake etc; Orange pigments include red yellow lead, molybdenum orange,
Permanent Orange GTR, Pyrazolone Orange, Palkan Orange, Industhrene Brilliant Orange R
K, Benzidine Orange G1 Ingense Len Brilliant Orange GK, etc.; Red pigments include Red Garla, Gadmium Red, Red Lead, Mercury Cadmium Sulfide, Permanent Red 4R1 Resolelet, Pyrazolone Red, Watching Red, Calcium Salt, Lake Red D1 Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B1 Alizarin Lake, Brilliant Carmiso 3
B, etc.; Purple pigments include manganese purple, 7 asto violet B, etc.
1 Methyl violet lake, etc.: Blue pigments include navy blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free 7-tricyanine blue, partially chlorinated phthalocyanine blue, fast sky blue, industhrene blue BC, etc. There is.

Green pigments include chrome green, chromium oxide, pigment green B1 malachite green lake, final yellow green G, etc.; white pigments include zinc white, titanium oxide, antimony white,
Zinc sulfide, etc. Extender pigments include palite powder, barium carbonate, clay,
Silica, white carbon, talc, alumina white, etc. Yellow coloring agents include benzidine yellow, hansa yellow, chromo-7 tar yellow, etc.

These colorants may be used alone or in combination of two or more, and may be organic or inorganic, as long as they are non-polluting and have high coloring power, and are not limited to these.

Other additives may be added to the toner of the present invention. For example, in order to impart chargeability, the following charge control agent may be used.

Metal complex salt compounds such as hydroxy-substituted naphthoic acid and its alkyl derivatives, hydroxy-substituted tetrahydronaphthoic acid, and alkyl derivatives of salicylic acid as those having good negative chargeability; or -form: (wherein, X is a hydrogen atom, Represents a lower alkyl group, lower alkoxy group, nitro group or halogen atom, n represents 1 or 2, m represents an integer of 1 to 3, X may be the same or different, M is chromium or cobalt atom, A''' represents hydrogen, sodium, potassium or ammonium ion); a metal complex compound represented by the formula:; and one form = (hereinafter,
Margin) (In the formula, xl and x2 are hydrogen atoms, lower alkyl groups,
represents a lower alkoxy group, a nitro group or a /%rogen atom, Xl and X2 may be the same or different, m and m' represent an integer of 1 to 3, R, and R
3 represents a halogen atom, R1 and R3 may be the same or different, n and n' represent integers of 1 to 3, R2 and R4 represent a hydrogen atom or a nitro group, M represents chromium or It represents a cobalt atom and K+ represents a hydrogen, sodium, potassium or ammonium ion. ) can be used as a charge control agent, but is not limited to the metal-containing oil-soluble dyes mentioned above. Also, 2-acrylamide-
By copolymerizing a sulfonic acid salt such as 2-methylpropane sulfonic acid with styrene or the like, the resulting so-called charge control resin can be used in combination with the above charge control agent to improve charge build-up and prevent toner scattering. can be reduced.

Electron-donating dyes, such as nigrosine dyes, are generally used to impart positive chargeability. In addition to these, alkoxylated amines, quaternary ammonium salts, alkylamides, phosphorus and tungsten alone or in combination, molybdate chelate pigments, dibutyltin oxide, and nitrogen-containing compounds may be used alone or in combination.

In addition, by using a copolymer of amino group-containing vinyl yarn picker such as dimethylaminoethyl methacrylate or diethylamine ethyl methacrylate with styrene or the like in combination with the above-mentioned charge control agent, charging rises quickly and toner scattering is reduced. can do.

The toner of the present invention may further contain other additives, such as waxes, as necessary, and various thermoplastic resins may be added to reduce the effect of the present invention in order to improve fixing properties. It may be used within the range where it is not.

Alternatively, the surface of the toner may be treated with ultrafine metal oxide powder.

The toner of the present invention uses the above-mentioned various material additives in known proportions, except for the amount of wax used, and uses the commonly used so-called pulverization method to reduce raw materials other than the main resin to 70%. They can be produced by a so-called suspension polymerization method in which they are dispersed and incorporated into a toner during polymerization of the resin, or a granulation method in which they are produced using a device such as spray drying, but are not particularly limited to these methods. Do not mean. Note that the average particle diameter of the toner can be arbitrarily selected from 5 to 20 μm.

The toner of the present invention can be formulated with a suitable carrier, for example.
It can be used as a component developer. As the carrier, resin-coated glass beads, steel balls, etc. are used when implementing the cascade development method, and ferrite, fine iron powder, or a so-called binder type carrier are used when implementing the magnetic brush development method. Further, the toner of the present invention itself may be manufactured as an insulating magnetic toner, and a magnetic brush development method may be implemented using this as a one-component developer.

Furthermore, it may be used as a toner when performing an impression development method or a tanti-down development method.

Hereinafter, this will be explained in detail by giving examples.

Preparation of Toners 1 to 5 Thermoplastic styrene acrylic resin 100 parts by weight Mn: 4,200 Mw: 210,900M
z: 1.323.000 My/Mn: 50.2
Mz/Mn: 315 Tg: 62. l'0 softening point = 115°C Acid value: 25-8 - Offset prevention additive 4 parts by weight Low molecular weight polypropylene (thermal decomposition product of polypropylene); 1
Viscosity at 60°C, 145 cps・8 parts by weight of carbon black MA#100 (manufactured by Mitsubishi Kasan Kogyo Co., Ltd.) ・More than 14 parts by weight of Bontron N-0 (manufactured by Orient Kagaku Kogyo Co., Ltd.; nigrosine dye) was placed in a 1OQ Henschl mixer. After mixing at 200Q rpm for 2 minutes, continuous extrusion kneading was performed using PCM30 (Mc132.5).

Next, after cooling, it is coarsely pulverized with a 2mm mesh 7-ether mill, finely pulverized with a jet pulverizer, and coarse and fine powders are cut with an air classifier to obtain particles with an average diameter of 11.2μm. I got a toner.

The surface of this toner is treated with 0.2% hydrophobic silica (R-974, manufactured by Nippon Aerosil Co., Ltd.).

The toner obtained in this manner is referred to as Toner 1.

A toner was prepared in the same manner as in Toner 1, except that the amount of anti-offset additive used in the preparation of Toner 1 was 1, 2, 1, 0, and 15 parts by weight per 100 parts by weight of resin. did. The obtained toner was designated as Toner 2.3.4.5.

Preparation of toner 6/Thermoplastic polyester resin 100 parts by weight Mn:
3,400 My: 213,400Mz:
1,183.200 My/Mn: 62.8Mz
/Mn: 348 Acid value: 16.7 Softening point = 10
9°C Tg: 64°C - Offset prevention additive 5 parts by weight Oxidized low molecular weight polypropylene (thermal decomposition product of polypropylene) Viscosity at 160°C: 140 cps Acid value: 5 - Carbon black 7 parts by weight (#44
; Mitsubishi Chemical Industries, Ltd.) Bontron 5-34 3 parts by weight (manufactured by Orient Chemical Industries, Ltd.; Cr-containing oil-soluble dye) or more was added in the same manner as in the preparation of toner 1 to obtain a toner with an average diameter of 10° and 4 μm. Ta. The obtained toner was designated as Toner 6.

The above thermoplastic resins include 55 Ch of bisphenol A/ethylene oxide adduct, 550 g of Bisphenol A/propylene oxide adduct, and 410 g of terephthalic acid.
g, trimellitic anhydride 45g, xylene 50g in 3Q
The mixture was placed in a flask and reacted at 240°C for 5 hours in a nitrogen stream, and then heated to 270°C and reacted for 8 hours. At this time, by-produced water was distilled off.

Preparation of Toner 7 (comparison) - Thermoplastic styrene/acrylic resin 100 parts by weight Mn: 12,800 Mw: 178,900
Mz: 957,600 Mw/Mn: 14.
0Mz/Mn: 75 Tg: 62.3℃ Softening point 127℃ ・Offset prevention additive 4 parts by weight Low molecular weight polypropylene carbon black used in toner 1 8
Parts by weight MA#1OO (manufactured by Mitsubishi Chemical Industries, Ltd.) - Parts by weight of Bontron N-014 (manufactured by Orient Chemical Industries, Ltd.) The above was made into a toner in the same manner as in the preparation of toner 1 to obtain toner 7 with an average diameter of 11.6 μm. Ta.

The surface of this toner was treated with 2 wt % of hydrophobic silica (R-974) (manufactured by Nippon Aerosil Co., Ltd.).

Preparation of i-toner 8 (comparison) - Thermoplastic styrene/acrylic resin 100 parts by weight Used in the preparation of toner 1 I; Offset prevention additive 4 parts by weight Viscoel 550p (viscosity at 160°C 240 cps) (Mitsubishi) (manufactured by Kasei Kogyo Co., Ltd.) ・Carbon black 8 parts by weight MA#
1OO (manufactured by Mitsubishi Chemical Industries, Ltd.) - Pontron N-014 parts by weight (manufactured by Orient Chemical Industries, Ltd.) Toner 8 was obtained in the same manner as in the preparation of Toner 1 using the above.

Preparation of Toner 9 (Comparative Example) Viscol 660p (160°C
Toner 9 was obtained in the same manner as Toner 8, except that Toner 9 (with a viscosity of 80 cps) (manufactured by Mitsubishi Chemical Industries, Ltd.) was used.

Preparation of Toners 10 to 12 Toners 10, 11, and 12 were prepared using the same recipe as for Toner 1, except that the following thermoplastic resins were used.

Toner 10 45 238 4400 61.
3 112 Toner 11 67 463 380
0 63.8 127 Toner 12 78 69
2 4800 66.2 138 Toner 13-15
Toner 13 was prepared in the same manner as in Example 15 except that low molecular weight borizlobyrene having the following viscosity was used.
．． 14.15 was adjusted.

Toner 13 120cps Toner 14
165cps toner 15 20
Production of 0 cps Carrier I - Styrene-acrylic resin 100 parts by weight (Prioride ACL; manufactured by Gutdeyer Co., Ltd.) Mapico Black BL-500 200 parts by weight (triiron tetroxide; manufactured by Titan Kogyo Co., Ltd.) - Carbon black MA#8 5 weight parts (manufactured by Mitsubishi Chemical Industries, Ltd.) The above materials were melted and kneaded using three rolls, solidified, then crushed and classified to obtain a magnetic carrier I having an average particle size of 35 μm.

Preparation of carrier ■ 100 parts by weight of polyester resin (resin obtained in toner preparation 6) 500 parts by weight of Zn-based ferrite (σm: 6
80e; He: l 35emu/g) (average particle thickness 0.4μ) ・Carbon black MA48 4 parts by weight or more was mixed in a 1Off Henschel mixer and then extruded by PCM
30 (Q/d 32.5), cooled and solidified, and then pulverized and classified to obtain a magnetic carrier (2) with an average diameter of 55 μm.

Evaluation of Toners Developers were prepared by combining toners 1 to 9 and carriers (1) or (2), and evaluated as described below. The results are shown in Table 1.

■Electrostatic charge measurement A total of 9 samples of toners 1 to 9 were made to a toner concentration of 10 wt% in the microcarriers I and II, and 60 g was placed in a 100 cc plastic bottle. The amount of charge (Qf) of each was determined after 30 minutes.

■Moisture resistance Charge attenuation after aging The charge amount was measured (One charge amount when mixed and stirred for 30 minutes: Qf (30 minutes)) The developer was placed in an environment of 35°C and 85% with the lid of the bottle opened. , left for 3 days t: Later charge amount (Qf(
35° C.-85%-3 days)), and the amount of attenuation of the charge amount after moisture resistance was determined using the following formula.

■ Heat Resistance Test Put 5g of toner in a glass sample bottle (50cc) and leave it in an oven at 506°C ± 0.5°C for 24 hours, then gently take it out, let it cool to room temperature, turn it upside down, and place the toner in a glass sample bottle (50cc). I checked to see if it would fall.

Rank A: Falling within 0 to 5 seconds, no agglomeration.

8 It falls within 5 to 15 seconds and does not aggregate. death.

C It fell between 15 and 30 seconds and fell lightly. It is agglomerated, but if you shake it well, it will return to its original state. There are no practical problems after returning to the ner.

D　30 seconds to 1 minute The degree of aggregation is weak, but even if shaken well, Not disintegrated.

E　It solidified at the bottom of the bottle without falling even after 1 minute.

■Fixing strength and nail release properties: The upper roller is coated with Teflon-based resin, and the lower is an LTV rubber roller with a pressure of 100 kg.
The temperature at which high-temperature offset and low-temperature offset occur when the toner is fixed at a speed of 45 cm/s using a fixing device that is in pressure contact with the toner and the fixing strength of ID1.2 and ID0.6 when fixing at 175° C. is determined.

High-temperature offset is a phenomenon in which the toner in contact with the hot roll melts and softens, and the toner adhering to the roller is transferred to the copy paper during the second rotation.On the other hand, low-temperature offset is a phenomenon in which the toner is not sufficiently melted by the hot roll. Since only the surface was melted, there was almost no fixation on the paper and the toner adhering to the hot roll was
This is a phenomenon in which the image is transferred to the copy paper during rotation.

ID is a value of image density measured using a Sakura reflection densitometer.

A strength of 80% or more is required for ID1.2 and 70% or more for ID0.6. Further, the non-offset width needs to be 100°C or more.

The fixing strength is determined by rubbing the copied image with a special device that places a 1 kg load on sandy poppy rubber so that the toner image does not disappear.

At this time, the ratio of the reflected temperature before and after rubbing with sand poppy rubber is 10
Expressed as a percentage of 0.

The nail separation test was evaluated by determining whether or not the nail marks made by the separating nails attached to the upper roller of the Teflon resin coat would damage the back side during double-sided copying. If the toner has high mold releasability, it will release naturally without relying on your nails, so there will be no nail marks.

The rank of the claw marks is ◎: No claw marks at all ○: There are very slight claw marks, but there is no practical problem. △: Claw marks are left ×: The text on the copy appears to be dragged by claw marks.

××＝Tear the paper due to poor separation It was expressed as If it is 0 or more, it is practical.

(Image test) Carrier (■) and toner 6 were placed in an IQ plastic bottle so that the toner concentration was 7 wt%, placed on a ball mill stand, and a developer was prepared at 120 rpm for 10 hours.

Put this developer into EP870 made by Minolta Camera Co., Ltd.
A printing durability test was conducted on K sheets, and the presence or absence of fog was evaluated and ranked as follows. On the other hand, excluding toner 6 <1-15
The toner was made into a developer in the same manner as the above-described toner, and a printing durability test was conducted using an organic laminated photoreceptor instead of the photoreceptor.

5: No fogging at all.

4: Slight fogging is observed.

3: Slight fogging, but no practical problem 2: Much fogging 1: Very much fogging In addition, the image density at the initial stage and after continuous printing of the IOK sheet was evaluated using a Sakura densitometer.

(2) Filming of toner on the photoreceptor If a part of the toner composition is filmed on the photoreceptor, the photosensitivity of the photoreceptor decreases, the residual potential increases, and fog occurs. The degree of this filming was measured using EP8 manufactured by Minolta Camera Co., Ltd.
70 (copy speed 35.0cm/s), IOK
The surface of the photoreceptor after the printing durability test was evaluated and ranked as follows.

◎: No filming at all.

○: The gloss of the areas touched by the developer is different from the areas that are not, but there is no problem in practical use.

△: Filming is continuous, and the proper position will shift unless you turn the exposure dial to overexpose by half a scale.

×: Clearly visible filming.

(When halftone is taken, the shading of the filming part and the non-filming part is created.) XX = There is no proper position on the exposure dial.

(Hereinafter referred to as margins) Effects of the Invention The toner of the present invention has excellent charge build-up and stability, and can provide good images with excellent fog and density.Especially in high-speed development systems, the toner has excellent fixability to transfer paper, etc. It has excellent separation properties from the fixing roller and can provide good images without offset.

Patent applicant: Minolta Camera Co., Ltd.

Claims (1)

[Scope of Claims] 1. A toner comprising at least a thermoplastic resin, a wax, and a colorant, wherein the thermoplastic resin has a number average molecular weight (Mn), a weight average molecular weight (Mw), and a z average molecular weight (Mz). , 1,000≦Mn≦7,000 40≦Mw/Mn≦70 200≦Mz/Mn≦500, and the viscosity of the wax at 160°C is 1
00 to 180 cps, and the wax is comprised in an amount of 2 to 10 parts by weight based on 100 parts by weight of the thermoplastic resin.